Juniper EX4300

Table 36: Details of the DC Power Supplies in EX4300 Switches (continued)
550 W DC Power SupplyDetails
2.43 lb (1.1 kg)Power supply weight
1Minimum installed in chassis
2Maximum installed in chassis
Install in power supply slots labeled PSU 0 and PSU 1 in the rear panel of
the chassis.
Power supply slots
InternalFans
•
Front-to-back, indicated by label AIR OUT (AFO)
•
Back-to-front, indicated by label AIR IN (AFI)
Airflow
IN OK and OUT OKPower supply status LEDs
4 ADC input current rating
–38 through –60 VDC
NOTE: The minimum input power required to power on the switch is
–43.5 +/– 0.5 VDC. After the switch is powered on, the operating range is
–38 through –60 VDC.
Operating range
To prevent electrical injury while installing or removing DC power supplies, carefully follow
instructions in “Installing a DC Power Supply in an EX4300 Switch” on page 236 and
“Removing a DC Power Supply from an EX4300 Switch” on page 238.
DC Power Supply Airflow
Each power supply has its own fan and is cooled by its own internal cooling system.
Each power supply has a label AIR OUT (AFO) or AIR IN (AFI) on the faceplate of the
power supply that indicates the direction of airflow in the power supply.
Table 37 on page 59 lists the DC power supply models and the direction of airflow in
them.
Table 37: Airflow Direction in DC Power Supply Models for EX4300 Switches
Direction of AirflowLabelonPower SupplyModel
Front-to-back—that is, air intake to cool the chassis is through the vents
on the front panel of the chassis and hot air exhausts through the vents
on the rear panel of the chassis.
AIR OUT (AFO)JPSU-550-DC-AFO-A
Back-to-front—that is, air intake to cool the chassis is through the vents
on the rear panel of the chassis and hot air exhausts through the vents
on the front panel of the chassis.
AIR IN (AFI)JPSU-550-DC-AFI-A
59Copyright © 2017, Juniper Networks, Inc.
Chapter 4: Power Supplies